Asus RT-AX88U LAN to WAN Speed problem

[Udi Burg]

Hi,
Followed threads here about similar issue with no results so I'm trying again.
I have a new Asus RT-AX88U with latest firmware.
I have 1000/100 Mbps Fiber internet connection with Fiber to Ethernet Converter.
When I connect a laptop to the FC converter and run a speed test against speedtest.net with CAT6 Ethernet cable I'm getting 980/110 Mbps with 1 Sec. TTL.
when I connect the same laptop with the same CAT6 cable to any on the LAN ports on the router, and connect the router to the FC converter with CAT6 cable the speed that I'm getting is 510/110 Mbps with 2 Sec. TTL.
I tried disabling QoS, WI-FI, enabled Jumbo frames and disabled them and many more settings with no luck.
Does anyone have a solution?
I also opened a ticket with Asus and waiting for their answer.
Any help will be highly appreciated.

Udi

 

[Yooshaw]

I have an AX88U as well, but only have 200/10 Mbps service. However, have noticed similar speeds as you when doing LAN to LAN speed tests with Iperf3, getting 500-600 both ways. When I hooked up an old Netgear router I had laying around, LAN to LAN went to 940 or so both ways. If you have another router handy, maybe test with that, if only to rule out the FC converter as the issue.

Have tried all kinds of tweaks to the settings with mine, and like you, no luck.

 

[Udi Burg]

I have an AX88U as well, but only have 200/10 Mbps service. However, have noticed similar speeds as you when doing LAN to LAN speed tests with Iperf3, getting 500-600 both ways. When I hooked up an old Netgear router I had laying around, LAN to LAN went to 940 or so both ways. If you have another router handy, maybe test with that, if only to rule out the FC converter as the issue.

Have tried all kinds of tweaks to the settings with mine, and like you, no luck.

Ho can the FC converter be the issue if when connecting a laptop directly to it I'm getting 980/100Mbps?

 

[Yooshaw]

Ah, misunderstood - I thought connecting directly was bypassing the converter.

 

[Udi Burg]

Still haven't heard from Asus Support

 

[Yooshaw]

Which LAN drop do you have your Laptop plugged into on the back of the AX-88U? I did find that drops 5-8 provided better speeds over 1-4.

 

[Udi Burg]

Which LAN drop do you have your Laptop plugged into on the back of the AX-88U? I did find that drops 5-8 provided better speeds over 1-4.

I'll check it. But better speed by far? Or just a little better?

 

[Yooshaw]

Better - gained about 100 Mbps

 

[Udi Burg]

Better - gained about 100 Mbps

OK, replaced the firmware with Merlin's one.
Followed these instructions: https://www.snbforums.com/threads/asus-rt-ax88u-wan-to-lan-speed-problem.56965/#post-588893
As well as disabling QoS and now I'm getting 980/110Mbps.
Still waiting to hear from Asus if this is a bug or a feature